Industrial Decarbonization: game-changers solutions with a special insight within electro-thermal energy storage (ETES)

The industrial sector still relies heavily on fossil fuels. Roughly 70% of industrial heat demand is based on fossil fuels, contributing to more than 9 billion tons of CO2 each year worldwide according to the International Energy Agency, equivalent to around 25% of global CO2 emissions.

As the world grapples with the urgent need to decarbonize industries, innovative technologies are emerging as potential game-changers. The most promising pathways for heat decarbonization identified are: electrification of heat in combination with thermal energy storage, zero-carbon heat sources, zero-carbon fuels, carbon capture and storage (CCS) or usage (CCU) and better heat management. The optimum mix of decarbonization options varies across industrial sectors and facilities due to differences in heat demand and local factors influencing practicality and economics [1].

• Opportunities for improving energy efficiency exist across all industrial subsectors, with potential efficiency gains ranging from 10% in cement to 15-20% in steel and plastics [1]. Digitalization and the Internet of Things offer avenues for automation and energy optimization, but significant energy efficiency improvements often entail high capital costs and longer payback periods, necessitating policy incentives for adoption. Heat storage systems present an opportunity to recover waste heat globally, with an estimated 2500 TWh recoverable globally [2], including 238.8 TWh/year just in the EU.
• Carbon Capture, Utilization, and Storage (CCU) is a promising technology for reducing industrial emissions by capturing CO2 from industrial processes and fossil fuel combustion. It allows for decarbonization without altering underlying fuels or industrial processes. However, CCUS technologies are energy-intensive and require additional energy input for operation. Low- or zero-carbon electricity is essential for making CCUS viable. Additionally, CCUS implementation necessitates significant investment in capital-intensive infrastructure.
• Zero-carbon fuels:

o??Hydrogen and ammonia are carbon-free combustible fuels, yielding primarily water and, in the case of ammonia, nitrogen upon combustion. However, challenges exits with the cost per unit of energy, the high inefficiencies in its production and with transport and storage.

o?? Biofuels can be broken into two categories: (1) the direct combustion of biomass to provide heat and (2) fuels synthesized from biomass via thermochemical or biochemical conversion processes. The direct combustion of biomass is often used where there is biomass waste. However, raw biomass has lower energy density and combustion temperature than coal and fuel oil, making transportation most costly. Thermochemical conversion methods like pyrolysis and gasification can convert biomass into synthetic substitutes for natural gas and fuel oil. To make these conversion technologies viable for industrial fuel production, efforts are needed to reduce capital costs and improve overall conversion efficiency.

o??Renewable natural gas (RNG) and synthetic natural gas (syngas) offer promising alternatives to traditional natural gas. RNG, derived from sources like agricultural waste and landfills, can be processed and utilized as a fuel, much like traditional natural gas. Both RNG and syngas can leverage existing pipeline infrastructure for distribution and can be directly used for heating purposes. However, the potential for emissions reduction with these alternative options depends on various factors, including methane emissions management, feedstock sources, and methane leakage throughout production and end-use phases.

• Zero-carbon heat like solar-thermal and geothermal energy present promising alternatives. Solar-thermal technology, particularly Concentrated Solar Power (CSP), utilizes mirrors or lenses to concentrate sunlight onto a receiver, generating energy for both electricity and direct industrial heat applications. However, CSP requires significant land and requires higher investment cost than other renewables like solar-PV. Intermittency is usually addressed by thermal energy storage. Geothermal energy taps into naturally occurring heat beneath the Earth's surface, providing reliable energy for heating, cooling, or electricity generation. Despite its reliability, geothermal faces geography constraints and it can lead to tectonic instability.
• Electrification of heat: The electrification of heat offers a promising pathway for decarbonization, leveraging low-carbon electricity sources. Many electrical technologies already exist commercially for process heating in specific applications or industries. Heat pumps offer a promising solution as they can provide more than one unit of useful heat for each unit of electricity input. However, barriers to wider adoption include high upfront capital costs, limited maximum temperatures, and integration challenges. Electric arc furnaces, which have been used in the steel industry for decades, can reach very high temperatures. Also electric boilers are a one-for-one replacement for existing fossil-fired boilers. Yet, the rigid, continuous energy demand of heat pumps, electric boilers, and furnaces will require substantial investment to build out the electricity grid. Moreover, during peak periods, electricity prices surge, significantly inflating the operational costs of electric boilers and furnaces. In this context, electrothermal energy storage (ETES), emerges as a pivotal solution for harmonizing electricity demand and supply, thereby mitigating the necessity for extensive grid expansion, reducing the electricity demand peaks between 6-30% in Europe as compared with other industrial electrification technologies. Moreover, ETES support the expansion of renewable electricity generation and it helps to reduce curtailment by harnessing surplus renewable during periods of high solar and wind generation. ETES can be also charge during off-peak periods, ensuring supply reliability when there is low local green energy availability, taking advantage of low energy-cost periods. It is worth mentioning that ETES is a commercially available technology, the round-trip efficiency is higher than 90%, it doesnt rely on critical raw materials and it has comperatively lower investment and operational cost than other solutions as shown in Figure 2.

After elucidating the diverse pathways available for heat decarbonization, in this article we will focus more on devling into the ETES solutions, recognizing its capability of enabling a faster transition to a clean industry. Since the viability of ETES is intrisically tied to the specific thermal requirement of industrial processes, the next section shifts towards providing a comprehensive overview of industries and industrial processes that are poised to benefit most from ETES integration.

Analysing the heat demand range of temperature in the most energy intensive industries and considering that the range of temperatures between 100 and 400oC is the most particularly favorable for the initial wave of ETES implementation, it becomes evident that sectors such as food and beverage, pulp and paper, textile, chemicals, and alumina emerge as prime candidates for ETES integration due to their substantial demand for temperatures within the specified range.

For instance, within the food and beverage sector, processes like (ultra)pasteurization (60-150oC), sterilization (70-130oC), cooking (100-240oC), baking (160-260oC) and evaporation (40-160oC) operate below 400oC. Similarly, in the paper industry, critical processes such as bleaching (130-150oC), pulp preparation (120-170oC), and drying (90-200oC) exhibit significant heat demand falling within the 100-400oC range. The textile industry also presents notable opportunities, with drying processes typically occurring between 100-130oC and fixing processes at 160-180oC. In the chemical industry, processes requiring temperatures below 400°C are quite common and varied. One such a process is? polymerization, in which reactions typically occur at temperatures ranging from room temperature to a few hundred degrees Celsius, depending on the specific monomers and desired polymer properties. Another example is distillation, which involves separating components of a mixture based on their boiling points.? Additionally, certain chemical reactions, such as oxidation or hydrolysis reactions, can occur at temperatures below 400°C to produce various chemical compounds. These processes are essential in the production of a wide range of products. Furthermore, in alumina refining, the digester vessel, which requires more than 60% of the energy use, operates at temperatures ranging from 150-270oC.

These industries represent a massive market for heat decarbonization solutions, with a heat demand in the range of 2840 TWh in the case of chemical and petrochemical industries, 2184 TWh in food, beverage, and tobacco, 1601 TWh in paper, pulp, and printing, and 693 TWh in textiles.

The convergence of substantial heat demand, compatibility in the range of temperature with mature ETES solution, and huge economic market size makes these industries prime candidates for exploring ETES solutions. By leveraging the unique capabilities of ETES to balance electricity demand and supply, reduce peak demand, and integrate renewable energy sources efficiently, businesses can achieve significant emissions reductions and cost savings.

If you're interested in exploring how ETES can help decarbonize your industrial energy demand and unlock potential emissions reductions and energy cost savings, feel free to reach out to us at [email protected]. Our team will conduct a thorough analysis of your case and provide tailored insights to support your sustainability goals.

[1] Clean heat pathways for industrial decarbonization, Center for Climate and Energy Solutions (C2ES), August 2021

[2] How big is the market potential for electrified thermal energy? Aurora Energy Research, November 2021.

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www.cepi.org Confederation of European Paper Industries